|Delicate skink or
(De Vis, 1888)
The delicate skink, dark-flecked garden sun skink, garden skink or plague skink (Lampropholis delicata) is a skink of the subfamily Lygosominae, originally from Eastern Australia. In its native range and in New Zealand it is also known as the rainbow skink, a term that usually refers to the African Trachylepis margaritifera, also a member of the Lygosominae.
It was accidentally introduced to New Zealand in the early 1960s. It is the only introduced reptile in New Zealand to successfully establish a wild population. It is found in several parts of the North Island, and occupies similar habitats to the native copper skink (Cyclodina aenea). The delicate skink is considered a pest species in New Zealand, as they reproduce much more rapidly than native lizards, and compete with other native lizards and mammals for food and habitat. They prey on many native invertebrates in the area as well.
It has also become naturalized in Hawaii, where it is reportedly now the most numerous skink, and on Lord Howe Island.
The delicate skink is more common in suburban gardens than in adjacent native bushland. It has a moderate body with a medium length, slender tail. Its scales are smooth. The back and sides are greyish-brown to rich brown, often with darker and paler flecks. A narrow yellowish-brown stripe is usually present on the outer edge of the back. The species can also have two distinct forms: a prominent white stripe and a less prominent white stripe. This dimorphism is not strictly distinguished by gender.
The females of the Lampropholis delicata species have a distinct color dimorphism. As of now, two morphs are known: a prominent white stripe and a dull white stripe along the lateral to midsection of the body. The continuation of each morph is often linked to its fitness advantage in crypsis but varies for each sex and temperature exposure. The presence of the stripe can confer a fitness advantage in females but in males the coloration may cause exposure to predation therefore the less distinct striped morph occurs more frequently in the males of the species. However the ultimate cause of this color dimorphism in not entirely conclusive for each sex but may be attributed geographical distribution, natural barriers, habitat preference, and sexual selection.
Since the Lampropholis delicata species is not native to the area in which they are found, it is possible that the resulting morphs are caused by the exposure to a new environment and climate as this particular species' activity level is temperature dependent. The most active males are found in lower temperature microhabitats and display a higher amount of individuals with indistinct stripes. This could be a result of anti-predation tactics. Females of this species do not display the same activity level as their male counterparts so the amount of females with the less distinct morphs remain lower. Sexual selection also plays a role on the continuation of this dimorphism because females seem to choose the males with higher fitness traits, in this case they favor the highly active less distinct striped males.
Aside from the variation in climate, Eastern Australia also provides different ground cover substrates as potential habitats. The species prefers an open substrate environment because the ground cover and loose leaf litter allows for thermoregulation, protection and optimal foraging conditions. Females and males remain sheltered in the leaf litter and their cryptic coloration adds an additional camouflage element but it is inconclusive as to whether the habitat distribution directly caused the color dimorphism.
Environmental factors greatly influence the change within the Lampropholis delicata species and continue to preserve each distinct variation. These polymorphisms have the potential to greatly affect survival in each niche, especially because the Lampropholis delicata is an invasive species, creating more need for adaptations.
- A new genus and a new species of skink from Victoria
- Lampropholis delicata, James Cook University
- "Plague skinks". Department of Conservation, New Zealand. Retrieved 16 October 2015.
- Joanne E. Peace (2004). Distribution, habitat use, breeding and behavioural ecology of rainbow skinks (Lampropholis delicata) in New Zealand, MSc thesis, Massey University. Retrieved 3 September 2010.
- Christopher Lever (2003). Naturalized reptiles and amphibians of the world, p. 101. Oxford University Press. ISBN 978-0-19-850771-0.
- Forsman, A. and Shine, R. (1995), "The adaptive significance of colour pattern polymorphism in the Australian scincid lizard Lampropholis delicata". Biological Journal of the Linnean Society, 55: 273–291.
- Peace, Joanne E. Distribution, habitat use, breeding and behavioural ecology of rainbow skinks (Lampropholis delicata) in New Zealand. Diss. Biological Sciences)--University of Auckland, 2004.
- Robert Howard, Ian Williamson and Peter Mather, "Structural Aspects of Microhabitat Selection by the Skink Lampropholis delicata", Journal of Herpetology, Vol. 37, No. 3 (Sep., 2003), pp. 613-617, http://www.jstor.org/stable/1566074?seq=3#page_scan_tab_contents
- Leimar, Olof, 2009 Environmental and genetic cues in the evolution of phenotypic polymorphism. 23: 125-135